Media channels, such as audio and video channels, have long been transmitted using application specific cables. For instance, two-core speaker cable is used to carry left and right audio channels from amplifiers to speakers.
More recently, media signals have been transmitted on computer based networks using protocols such as unicast or multicast. Unicast is a method of sending packets on a computer network to a single destination. The unicast packets must be retransmitted for every media device that wishes to receive the packets.
Multicast is typically used to refer to IP multicast, which is a protocol for efficiently sending to multiple receiver devices at the same time on TCP/IP networks by use of a multicast address. The computer network then operates to route the packets to each of the devices on the network that wish to receive the multicast packets.
Media networks can allow for redundant media packet streams to be transmitted and received. It is known for the transmitter to continually process the primary media packet stream and simply ignore the redundant copy of the media packet stream. In the event that a problem is detected in the primary packet stream (i.e. a broken transmission path in the network) a “fail-over” switch is enacted. Once the switch is activated, the receiver device then ignores the primary media packet stream and processes the redundant copy.